package kotlinx.coroutines

import kotlinx.coroutines.flow.*

/**
 * Marks declarations in the coroutines that are **delicate** &mdash;
 * they have limited use-case and shall be used with care in general code.
 * Any use of a delicate declaration has to be carefully reviewed to make sure it is
 * properly used and does not create problems like memory and resource leaks.
 * Carefully read documentation of any declaration marked as `DelicateCoroutinesApi`.
 */
@MustBeDocumented
@Retention(value = AnnotationRetention.BINARY)
@RequiresOptIn(
    level = RequiresOptIn.Level.WARNING,
    message = "This is a delicate API and its use requires care." +
        " Make sure you fully read and understand documentation of the declaration that is marked as a delicate API."
)
public annotation class DelicateCoroutinesApi

/**
 * Marks declarations that are still **experimental** in coroutines API, which means that the design of the
 * corresponding declarations has open issues which may (or may not) lead to their changes in the future.
 * Roughly speaking, there is a chance that those declarations will be deprecated in the near future or
 * the semantics of their behavior may change in some way that may break some code.
 */
@MustBeDocumented
@Retention(value = AnnotationRetention.BINARY)
@Target(
    AnnotationTarget.CLASS,
    AnnotationTarget.ANNOTATION_CLASS,
    AnnotationTarget.PROPERTY,
    AnnotationTarget.FIELD,
    AnnotationTarget.LOCAL_VARIABLE,
    AnnotationTarget.VALUE_PARAMETER,
    AnnotationTarget.CONSTRUCTOR,
    AnnotationTarget.FUNCTION,
    AnnotationTarget.PROPERTY_GETTER,
    AnnotationTarget.PROPERTY_SETTER,
    AnnotationTarget.TYPEALIAS
)
@RequiresOptIn(level = RequiresOptIn.Level.WARNING)
public annotation class ExperimentalCoroutinesApi

/**
 * Marks [Flow]-related API as a feature preview.
 *
 * Flow preview has **no** backward compatibility guarantees, including both binary and source compatibility.
 * Its API and semantics can and will be changed in next releases.
 *
 * Feature preview can be used to evaluate its real-world strengths and weaknesses, gather and provide feedback.
 * According to the feedback, [Flow] will be refined on its road to stabilization and promotion to a stable API.
 *
 * The best way to speed up preview feature promotion is providing the feedback on the feature.
 */
@MustBeDocumented
@Retention(value = AnnotationRetention.BINARY)
@RequiresOptIn(
    level = RequiresOptIn.Level.WARNING,
    message = "This declaration is in a preview state and can be changed in a backwards-incompatible manner with a best-effort migration. " +
            "Its usage should be marked with '@kotlinx.coroutines.FlowPreview' or '@OptIn(kotlinx.coroutines.FlowPreview::class)' " +
            "if you accept the drawback of relying on preview API"
)
@Target(AnnotationTarget.CLASS, AnnotationTarget.FUNCTION, AnnotationTarget.TYPEALIAS, AnnotationTarget.PROPERTY)
public annotation class FlowPreview

/**
 * Marks declarations that are **obsolete** in coroutines API, which means that the design of the corresponding
 * declarations has serious known flaws and they will be redesigned in the future.
 * Roughly speaking, these declarations will be deprecated in the future but there is no replacement for them yet,
 * so they cannot be deprecated right away.
 */
@MustBeDocumented
@Retention(value = AnnotationRetention.BINARY)
@RequiresOptIn(level = RequiresOptIn.Level.WARNING)
public annotation class ObsoleteCoroutinesApi

/**
 * Marks declarations that are **internal** in coroutines API, which means that should not be used outside of
 * `kotlinx.coroutines`, because their signatures and semantics will change between future releases without any
 * warnings and without providing any migration aids.
 */
@MustBeDocumented
@Retention(value = AnnotationRetention.BINARY)
@Target(AnnotationTarget.CLASS, AnnotationTarget.FUNCTION, AnnotationTarget.TYPEALIAS, AnnotationTarget.PROPERTY)
@RequiresOptIn(
    level = RequiresOptIn.Level.ERROR, message = "This is an internal kotlinx.coroutines API that " +
            "should not be used from outside of kotlinx.coroutines. No compatibility guarantees are provided. " +
            "It is recommended to report your use-case of internal API to kotlinx.coroutines issue tracker, " +
            "so stable API could be provided instead"
)
public annotation class InternalCoroutinesApi

/**
 * Marks declarations that cannot be safely inherited from.
 */
@Target(AnnotationTarget.CLASS)
@RequiresOptIn(
    level = RequiresOptIn.Level.WARNING, message =
    "Inheriting from this kotlinx.coroutines API is unstable. " +
        "Either new methods may be added in the future, which would break the inheritance, " +
        "or correctly inheriting from it requires fulfilling contracts that may change in the future."
)
public annotation class ExperimentalForInheritanceCoroutinesApi

/**
 * Marks declarations that cannot be safely inherited from.
 */
@Target(AnnotationTarget.CLASS)
@RequiresOptIn(
    level = RequiresOptIn.Level.WARNING, message =
    "This is a kotlinx.coroutines API that is not intended to be inherited from, " +
        "as the library may handle predefined instances of this in a special manner. " +
        "This will be an error in a future release. " +
        "If you need to inherit from this, please describe your use case in " +
        "https://github.com/Kotlin/kotlinx.coroutines/issues, so that we can provide a stable API for inheritance. "
)
public annotation class InternalForInheritanceCoroutinesApi
